Crank-arm connection.



No. 737,603. PATENTED SEPT. 1, 1903. J. S. FRITZ.

GRANK ARM CONNECTION. APPLICATION FILED FEB. 16, 1903 N0 MODEL.

y (at W Patented September 1, 1903.

PATENT OFFICE.

JACOB S. FRITZ, OF ZANESVILLE, OHIO.

CRANK-ARM CONNECTION.

SPECIFICATION forming part of Letters Patent No. 737,603, datedSeptember 1, 1903.

Application filed February 16, 1903. Serial No. 143,5 76. (No model.)

To all whom it may concern:

Be it known that I, JACOB S. FRITZ, a citi zen of the United States,residing at Zanes ville, in the county of Muskinguin and State of Ohio,have invented a certain new and usef Lil Improvement in Crank-ArmConnections, of which the following is a specification.

This invention relates to means for connecting crank-arms to shafts, andis particularly designed for connecting pedal crankarms to thedrive-shafts of bicycles, and while the embodiment shown intheaccompanying drawings illustrates its application to a bicycle itwill of course be understood that it may be used in other connections aswell.

In view of the fact that the crank-hangers of bicycles now on the marketvary considerably in length difficulty is experienced in fitting a newshaft and pedal-cranks to a machine, as the shaft is either too long ortoo short for the hanger. This objection is effectually overcome by thepresent invention, which has for its object to provide a shaft of alength exceedingihe greatest length of the crank-hanger and to arrangefor conveniently fitting a pedal crank-arm thereto and adj usting thesame in accordance with the length of any particular crank-han gerwithout altering or changing the latter in any manner whatsoever.

lVith this object in view the present invention consists in thecombination and arrangement of parts, as will be hereinafter more fullydescribed, shown in the accompanying drawings, and particularly pointedout in the appended claims, it being understood that changes in theform, proportion, size, and minor details may be made within the scope.of the claims without departing from the spirit or sacrificing any ofthe advantages ofthe invention.

In the drawings, Figure 1 is a front elevation of a crank-hanger havingthe features of the present invention applied thereto. Fig. 2 is adetail perspective view of a shaft constructed in accordance with thepresent invention and having an integral pedal-arm Fig. 3 is a detailsectional view on the line 2 of Fig. 1.

Like characters of reference designate cor responding parts in each andevery figure of the drawin The preferred embodiment of my invention sofar as the shaft itself is concerned has been shown in Fig. 3, whereinthe reference character 1 designates a shaft which is preferablyprovided at one end with an integral pedal crank-arm 2; but it will ofcourse be understood that this arm may be integral or otherwiseconnected with the shaft without affect- 'ing the present invention.VVherein the present form of shaft differs from the common or ordinaryshaft resides in the fact that it is considerably longer than isabsolutely necessary for the crankhanger, the latter being designated bythe reference character 3 in Fig. 1. In addition to this firstmentioneddifference that end of the shaft which is opposite the arm 2 isscrew-threaded, as indicated at 4, for about one-half of its length, andthese screw-threads are cut away or interrupted to form a flattenedlongitudinal portion 5, extending throughout the entire length of thescrew-threaded portion and leading inwardly from the adjacent end of theshaft. \Vhen this improved shaft is fitted to an ordinary crank-hanger,it will be seen that the screw-threaded end thereof projects beyond oneend of the hanger in order that the interiorly-screw-threaded terminaleye portion 6, which extends entirely through a detachable pedalcrank-arm 7, may be fitted thereto and screwed up snugly against theconetightening ring or nut 8. To prevent the crank from backing off ofthe shaft, the arm 7 is provided with an interiorly smooth and taperedopening 9, extending transversely therethrough and intersecting the eyefor the reception of a tapered cotter-pin 10, which has a flattenedportion 11 to bearsnugly across the flattened portion 5 of the shaft andthere by interlock the crank-arm and the shaft for simultaneous movementand to prevent the arm from backing off of the shaft. To preventloosening and displacement of the cotter-pin, the smaller end thereof isprojected beyond the arm and is screw-threaded for the reception of asuitable nut 12. After the detachable arm 7 has thus been secured to theshaft the projected portion of the latter is cut off flush with theouter face of the eye (3.

I am aware of the fact that a crank-arm has been connected to a shaft bymeans of a cotter-pin passed through the eye portion of the arm andengaging a notch in the shaft, but appreciate the fact that in using anotch of a size to fit the pin the arm must be connected at one pointand at one point only to the shaft, and therefore cannot be adjustedlongitudinally of the shaft and locked or fastened at any point thereon.This difficulty is effectually obviated by providing the long continuousflattened portion 5 on the shaft,whereby the crank-arm may be adj ustedlongitudinally to any point and then interlocked with the shaft by meansof the cotter-pin 10. Furthermore, the opening or eye in the crank 7extends entirely through the same in order that the shaft may beprojected entirely through the crank, as shown in Fig. 1 of thedrawings, or, in other words, to permit of the crank being adjusted toany point of the screwthreaded portion of the shaft and not limited to aposition at the extremity of the shaft.

From the foregoing description it will be understood that the essentialobject of the present invention is to provide a crank-shaft and adetachable pedal crank-arm therefor which are particularly adapted foruse in repair-shops, wherein the workman may have a shaft'which islonger than any size of crankhanger and may be fitted to anycrank-hanger 3. The combination with a crank-hanger, of

a shaft j ournaled therein and having one end projected externally ofthe erank-han ger, said projected end portion being screw-threaded andflattened longitudinally throughout said screw-threaded part, acrank-arm having an interiorly-screw-threaded eye fitted to theprojected end portion of the shaft, and a pin piercing the eye andengaging the flattened portion of the shaft to adjustably interlock thearm thereon.

l. As a new article of manufacture, a pedalcrank embodying a shafthaving a pedal-arm at one end and a screw-threaded portion at theopposite end thereof, a portion of the shaft being removed from thescrew-threaded part thereof to form a fiat face leading inwardly fromthe adjacent end of the shaft for engagement by a cottenpin.

5. As a new article of manufacture, a pedalcrank embodying a shafthaving a pedal-arm at one end and a screw-threaded portion at theopposite end thereof, a portion of the shaft being removedlongitudinally from the threaded part thereof at a point diametricallyopposite the pedal-arm to form a broad fiat face leading inwardly fromthe adjacent endof the shaft for engagement by a cotter-pin.

JACOB S. FRITZ.

In presence of- A. L. PHELPS, W. L. MORROW.

